Multiple Mating of Enhance the Number of Female Progeny but Shorten the Longevity.

The female adult is an important arrhenotocous parthenogenesis parasitoid of , and its reproductive mode is beneficial for the population continuation of by way of multiple mating and backcross. To explore the effect of mating on the population fitness and control efficiency of , its mating frequency and backcross were observed under laboratory conditions. The results showed that most matings in involved four distinct stages: courtship, pre-copulatory, copulation, and post-copulatory behaviours. Only the duration of courtship increased significantly with an increase in copulation frequency for females, and the courtship duration of females mated with different males were significantly shorter than those mated with the same male at the same mating times, which suggested that females might prefer to mate with different males to enrich the genotype of their offspring. The total number of mummified aphids and the female and male longevity decreased significantly with an increase in mating frequency. On the contrary, female progenies increased significantly with an increase of mating frequency, suggesting that sperm limitation might occur in females when they only mated once. These results imply that females might prefer to receive more sperm by mating multiple times in their life span. In addition, we found that the intrinsic rate of increase () of of the control group (0.2858 d) was significantly greater than that in the backcross treatment (0.2687 d). The finite killing rate () of of the control group was similar to that in the backcross treatment, which showed that this treatment had a negligible negative effect on the control efficiency of . In conclusion, the results showed that multiple mating increased the number and proportion of female progenies but shortened the longevity of female and male adults, while the negative effect of backcross on the control efficiency of was negligible.